1. Field of the Invention
The invention relates to a device for guiding a saddle pole in a cladding tube
2. The Prior Art
Saddle poles for fastening bicycle saddles are usually fixed in the saddle tube with a mechanical clamp. Consequently, the saddle tube is generally slit at the upper end so that the periphery of the tube is reduced by the clamping effect and thus the saddle tube bears upon the saddle pole with a positive fit. The clamp is tightened with a screw and nut connection or a quick clamping device is used, at which the clamping force is reached by changing the position of a lever. Such a “quick release lever” enables to adjust the height of the saddle and to fix it without tool. This is for example necessary if the bicycle is going to be ridden by people of different size or if the saddle should be adapted for one and the same rider using certain parameters. Such is the case for instance when riding in difficult terrain, as in particular in mountain biking with mountain bikes. Uphill, the height of the saddle must be adjusted optimally from an ergonomic viewpoint so as to achieve good power transmission. When going downhill, the rider must shift his centre of gravity backwards and downwards according to the steepness and to the difficulty and to that end he must often bring his buttocks behind the saddle. The deeper the saddle, the easier the rider can shift his centre of gravity actively and dynamically, but thereby also loses on cornering forces which he can apply with the inside of its thighs against the saddle when the latter is accordingly in a raised position. The optimal height of the saddle therefore depends on the respective riding condition.
The shortcoming of the described clamping devices lies in that the rider must dismount every time and adjust the height of the saddle. Different devices for (semi-automatic) height adjustment of a bicycle saddle are therefore already offered on the market, which the rider can adjust while riding his bike.
Since these semi-automatic saddle poles (as described for instance in document DE 10 2010 044 356.5) are not clamped any longer in their respective position as mentioned above, but rather locked via a pin or similar or for instance fixed hydraulically, they naturally have a clearance, which is necessary on the one hand so that the height of the saddle pole can be adjusted easily, which is undesirable on the other hand while riding his bike, i.e. when the saddle pole is locked, because the rider has a mechanically unstable feeling.
A height adjustable saddle pole is disclosed in the international patent application WO 2007/117884 A2, which is run in the cladding tube by means of a bushing (FIG. 2, reference sign 74). This known saddle pole also includes slide blocks or groove blocks which engage into corresponding grooves of a cladding tube. These groove blocks are used however exclusively for preventing rotation of the saddle pole, but not for guiding it in the cladding tube.